What causes leukaemia?

The “two-hit hypothesis” proposes that initiating events take place whilst the child is still in the womb, with a second ‘hit’ later in life triggering the development of full-blown leukaemia.

Childhood leukaemia is not a hereditary disease so children do not inherit the disease from their parents. However, there are a number of different genetic mutations linked to the disease and scientists have shown that these mutations are already present when the child is born.

Not all children born with the mutations will develop leukaemia. For example, the ‘TEL-AML1’ mutation is present in around 1% of new born babies but less than 1% of those born with this mutation will actually develop leukaemia.

This suggests that whilst the development of childhood leukaemia is initiated when the child is still in the womb some other factor may trigger the development of full-blown leukaemia later in life. This is known as the “two-hit hypothesis”.

Environmental and lifestyle factors

The incidence of childhood leukaemia increased steadily throughout the twentieth century at a rate of approximately 1% per year.

This suggests that factors linked with our modern lifestyle may have increased the risk of our children developing leukaemia. These factors may exert their effect either before or after birth.

Because of the relatively low number of children developing leukaemia each year and of the multi-factorial nature of the disease, it is often very difficult to establish associations with particular factors.

Studies have reported associations between childhood leukaemia and a number of environmental and lifestyle factors, with varying degrees of certainty.

Some of these factors – such as exposure to ionising radiation or certain chemicals – have been linked with an increased risk of developing childhood leukaemia.

Other factors have been linked with a decreased risk of developing the disease. Breast-feeding is a factor that has been shown to have a protective effect.

Why is it important to research the causes?

The increased incidence of childhood leukaemia suggests that there is something about our modern lifestyle which has raised the risk of our children developing the disease.

If we can understand what elements of our changing lifestyle are putting our children in danger, we may be able to take steps to reverse the increasing incidence.

Improving our understanding of the causes of childhood leukaemia and the mechanisms by which it develops may also give us a better insight into ways of treating the disease.

Causes of childhood leukaemia factsheet (PDF. 140KB. New window will open)

"Do electric and magnetic fields cause childhood leukaemia?"(PDF. 870KB. New window will open)

Our programme of researchRead more about our programme of research into the causes of childhood leukaemia.